In motor control apparatus mounted in hybrid vehicles and electric vehicles, direct current voltage supplied from a direct current power source is converted by an inverter to alternating current voltage to drive a motor generator (MG). The electric current flowing in each phase of the motor generator MG is detected by a current sensor, and a voltage command value to be applied to a coil of each phase of the motor generator MG is calculated. The inverter, on the basis of the voltage command for the coil of each phase, turns a switching transistor on and off to drive the motor generator MG with a torque command value which is instructed. In such a motor control apparatus, it is necessary to reliably detect and cope with various abnormality modes associated with the motor control.
Patent Document 1 discloses a motor drive controller including an abnormality detection unit for detecting an abnormality of a motor based on a torque command value requested for the motor and an estimated actual torque which is actually generated in the motor. Patent Document 1 further discloses that driving current of each phase to be supplied to the motor is detected and q-axis current which is a torque current component of the motor is calculated based on the detected driving current, and the actual torque is estimated from the calculated q-axis current, the magnetic flux of the motor, and the angular speed of the motor.
Patent Document 2 discloses detecting current of a first phase (e.g. U-phase) and current of a second phase (e.g. V-phase) of three-phase alternating current flowing in a three-phase alternating current motor, obtaining an integrated value of a first-phase current value detected for a predetermined time period and an integrated value of a second-phase current value detected for a predetermined time period and comparing these values, and determining an abnormality of a current sensor when a difference between these values exceeds a predetermined value.